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Notifiable diseases online

Notifiable Diseases Online presents information based on data from the
Canadian Notifiable Disease Surveillance System (CNDSS). Nationally
notifiable diseases are infectious diseases that have been identified
by the federal government and provinces and territories as
priorities for monitoring and control efforts. Through the CNDSS,
provinces and territories voluntarily submit annual notifiable disease
data, which are used to produce national disease counts and rates. The
Notifiable disease charts
can be used to explore trends in annual national counts and rates
of reported cases of nationally notifiable diseases since 1924,
where available.

The list of nationally notifiable diseases has been revised
periodically. A disease that has been taken off the list can be
reintroduced later if its status in Canada changes. Though in early
years the decision to place a disease on the list relied on expert
opinion, since 1987 these decisions have been based on
federal/provincial/territorial consensus using set criteria
Footnote 1.
The
List of notifiable diseases
provides the disease names and years in which they were considered
notifiable.

Case definitions

Case definitions are the detailed descriptions used to identify cases
of disease.
Case definitions
include the clinical signs and symptoms that define the appearance of
the disease and the laboratory criteria for disease confirmation based
on current national and international guidelines, literature review,
and diagnostic laboratory practices and technology.

Exploring notifiable diseases data

General notes

Cases reported only represent a portion of all the cases in the population. Cases may not be reported for the following reasons:

Not all people will seek medical attention

Reporting of diagnosed cases is not complete

Diagnostic tests may result in a false negative

Interpretation of the characteristics of a disease may vary. This is particularly true prior to 1990, when the first national case definitions were produced.

Not all provinces or territories are able to report on all diseases in every year. Where a province or territory has not reported, it is noted in the limitations that appear with a disease selection. A province or territory not reporting does not necessarily mean that there have been no cases of the selected disease.

Additional limitations specific to the disease or time period selected are listed under the requested table/graph and are important for interpretation of the data shown.

Not all of the diseases that have ever been nationally notifiable are available in the charts. Diseases have not been included when the period of notifiability was short, the disease is no longer notifiable and was rare during its period of notifiability, or completeness and/or consistency of reporting was poor.

Age and sex breakdowns are available only from 1991 onwards.

Only confirmed cases of disease are included, unless otherwise specified.

Due to periodic updates of the historical surveillance data, counts and rates for a particular disease and year may change over time.

Denominators used for rate calculations

Congenital and/or perinatal diseases:

1979 to 1990: Because live birth data were not available for this period, estimates were calculated using the proportion of low birth weight births in the given years from, “Low birth weight (less than 2,500 grams) and borderline viable birth weight-adjusted low birth weight (500 to less than 2,500 grams), by sex, Canada, provinces and territories, annual”. Source: Statistics Canada, CANSIM Table 102-4005 (Accessed 2013-08-01).

Please note that the number of births is final up to December 2013 and updated from January 2014 to December 2016.

All other diseases:

1924 to 2010: Final intercensal population estimates were used for calculating the appropriate denominators for rate calculations. The intercensal population estimates are final and remain stable over time. Source: Statistics Canada, Demography Division

2011 to 2016: Population estimates used to calculate denominators for the years 2011 to 2016 were as follows (Source: Statistics Canada, Demography Division):

2011-2013: Final postcensal population estimate

2014-2016: Updated postcensal population estimates

Population estimates are subject to updates over time.

How to use Notifiable diseases online

This website provides data on nationally notifiable diseases including
the counts and rates of reported cases, data limitations and disease
descriptions. You are given the option to view Simple Charts, Custom
Charts, or perform large data extracts. For the charts, a graphical
representation of the data is displayed based on the type of chart and
parameters selected. The source data table, limitations of the data
and descriptions for the selected notifiable disease(s) are also
provided.

Careful consideration must be given when interpreting the data
displayed in these charts and tables due to both limitations of the
data and limitations of the chart functionality. When using the chart
applications, it is also important to note that some diseases will be
marked with “N/A” in the tables. These are diseases which either were
not nationally notifiable in the years(s) selected, were not reported
by any province/territory in the selected year(s), or for which the
age/sex breakdown may not be available/relevant. Note that lack of
reporting does not necessarily mean that there were no cases.

"Print PDF" and "Excel export" buttons are located within the "Query
Filters" section. The "Print PDF" button produces a printable PDF
document that contains the chart, source data table, data limitations
and disease descriptions. The "Excel export" button creates a
Microsoft Excel workbook containing the data limitations and disease
descriptions in the "Notes" tab and the data table in the "Data" tab.